Bone Healing Flashcards
What are the causes of stress and injury?
Hypoxia - lack of oxygen Ischaemia - lack of blood flow Infectious agents Physical and chemical agents Genetic abnormalities Metabolic alterations Nutritional imbalance
What is hyperplasia?
Increase in cell number
Driven by hormones and growth factors
Name and describe the different types of cells
Labile cells = continuously dividing e.g. skin cells
Stable cells = can divide in response to injury
Permanent cells = cardiomyocytes and neurons
Describe hypertrophy
Increase in cell size
Describe atrophy
Decrease in cell size
Describe metaplasia
Reversible replacement of one mature cell type by another
Describe morphological changes in cells by necrosis (focus on nucleus changes)
Nuclear pyknosis (dark pinpoint nucleus)
Karyorrhexis (fragmented nucleus)
Karyolysis ( nucleus disappears)
Throughout there is an increase in eosinophilia
Define an infarct.
Localized area of tissue necrosis due to cut off of its blood supply
Name causes of inflammation
Infections Trauma and tissue necrosis Physical and chemical injury Foreign bodies e.g. sutures Immune reactions e.g. hypersensitivity, autoimmunity
Name the main processes of acute inflammation
Vasodilation
Increased permeability of microvasculature
Emigration of leukocytes
* Review notes for more detail*
Name the steps of leukocyte migration
1 - margination 2 - adhesion and rolling 3 - diapedesis and transmigration 4 - chemotaxis *** Review notes for details ***
What is the function of histamine?
Vasodilation, increased vascular permeability
What is the function of prostaglandins?
Fever, pain, vasodilation
What is the function of cytokines (TNF, IL-1, IL-6)
Endothelial activation (expression of adhesion molecules), fever
What is the function of the complement system?
Chemotaxis
Name the different patterns of acute inflammation
Purulent (supprative) inflammation
Serous Inflammation
Fibrinous Inflammation
What is an abscess?
A localized collection of pus
Name the main cells involved in chronic inflammation
Macrophages, lymphocytes, plasma cells
Name the systemic affects of inflammation
Fever
Leukocytosis
Acute phase proteins
What can occur in healing?
Either scarring or regeneration
Describe the process of healing by fibrosis.
Formation of new capillary vessels (angiogenesis)
Formation of granulation tissue
Maturation then remodeling of fibrous scar (matrix metalloproteinases - MMPs)
List factors affecting tissue repair
Wound infection
Diabetes
Nutritional status (protein and vitamin C deficiency decreases collagen synthesis)
Glucocorticoids (decreases collagen synthesis)
Poor blood supply
Mechanical factors (excess movement)
Foreign body in wound
